A vehicle including an internal combustion engine may include a turbocharger having a turbine. The turbine may be coupled to the engine via one or more exhaust passages. Exhaust gases flow from the engine, through the exhaust passages, and into an inlet end of a housing of the turbine, where the exhaust gases expand to drive the turbine. The exhaust gases may then flow out of an outlet end of the turbine and toward an emissions control device. The emissions control device may be a catalytic converter configured to remove hazardous substances such as carbon monoxide (CO), nitrogen oxides (NOx), unburned hydrocarbons (HC), sulfur oxides (SOx), and/or other compounds from the exhaust gases.
The outlet end of the turbine and an inlet end of the emissions control device are often coupled to opposite ends of an exhaust conduit by one or more fastening devices such as bands, v-clamps, etc. in order to flow exhaust gases from the turbine, through the conduit, and to the emissions control device. One example approach is shown by Schmitt et al. in U.S. Pat. No. 9,140,171. Therein, a flange is disclosed which includes a pipe section projecting away from the flange along a longitudinal center axis, with the center axis being perpendicular to a plane of the flange. The flange includes a plurality of fastening areas arranged radially outward from the pipe section, and the flange can be fastened to a complementary counter flange via the fastening areas (in order to couple an exhaust pipe to a catalytic converter, for example). Another example approach is shown by Loebig in U.S. Pat. No. 8,585,101. Therein, a flange connection is provided for a turbocharger and an exhaust system. The flange connection includes a clamping bracket that engages over flanges provided on the turbocharger and on the exhaust system and clamps them with one another using at least one screw, which, using a screw thread provided in the clamping bracket, exerts pressure on a pressure part, which in turn exerts pressure on the edges of the flanges.
However, the inventors herein have recognized potential issues with such systems. As one example, radially extending a location of tabs, as shown in Schmitt, configured to receive a bolt or a screw for connecting flanges may result in degradation of the tabs due to vibrations and heat due to engine combustion. Additionally, a distance between a catalyst and the turbine housing may be relatively large due to the accessibility of the tabs. For example, an assembly worker may use a drill or other similar device to thread a bolt or screw through the tabs. As such, a distance between the catalyst and the turbine housing may be dependent based on a size of the drill. As another example, the clamping bracket of Loebig may present certain challenges. For example, the clamping bracket is aligned with an opening in a flange prior to a screw being threaded therethrough by an assembly worker. This presents assembly challenges which may increase manufacturing costs and decrease a manufacturing efficiency.
In one example, the issues described above may be addressed by a system comprising a turbine housing comprising a first passage arranged within a first flange configured to centrally align with a second passage arranged within a chamfer of a second flange of a catalyst housing and a fastener passing through the second passage and locked with the first passage. In this way, the first and second passages are angled relative to a central axis of the catalyst housing, allowing a distance between the turbine housing and the catalyst housing to decrease.
As one example, a fastener may pass through the second passage and couple to the first passage. Once the fastener is locked with the first passage, flat surfaces of the first and second flanges may be pressed together in face-sharing contact. To fasten the fastener to the first passage, a tool (e.g., a drill) is used to rotate the fastener about a central axis of the first and second passages. By angling the second passage via the chamber, the fastener may be accessed by the tool in a location generally away from the catalyst housing. This may allow a distance between the catalyst housing and the turbine housing to be reduced relative to the examples of Schmitt and Loebig. By doing this, heat loss may be mitigated, packaging constraints may be reduced, and emissions may decrease.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.